Study on the physicochemical properties and immunomodulatory anti-tumor effect of the Pholiota adiposa polysaccharide

Abstract

In this study, the extraction, purification, physical and chemical properties, and biological activity of the Pholiota adiposa (PAP) polysaccharide were investigated. One fraction (PAP-1a) of Pholiota adiposa polysaccharides was isolated using DEAE Sepharose™ Fast Flow and Sephacryl™ S-300 High-Resolution columns. The HPLGPC results revealed that the molecular weight of PAP-1a was 16.453 kDa. PAP-1a was composed of mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, xylose, arabinose, and fucose and their molar % was 33.41, 0.53, 1.33, 0.07, 0.27, 5.28, 38.31, 0.83, 18.04 and 2.23, respectively. PAP-1a could activate macrophages to secrete NO and cytokines such as TNF-a, IL-6, and IL-12p70. When hepatocellular carcinoma cells (HCCs) and macrophages were co-cultured, it was observed that PAP-1a inhibited the growth of Hep-G2, Hep-3B, and Huh7 via immunoregulation. It triggered cell apoptosis by blocking the cell cycle in the G0/G1 stage. Furthermore, PAP-1a had no direct cytotoxicity against the hepatocyte cell line L02 and macrophages RAW264.7.